Selective signaling by electromagnetic waves.



No'. 715,203. y Patented nec.'2, |902.

- B. A. FESSEMDEN.' SELEGTIVE SGNALIKG `BY ELECTROHGNETIC WAVES. Y (Applikation med Nav. 1a, 1902.1

(No Model.) 2 Sheets-Shaat L Engl. l l

775192655 es: Y lnyefzor:

Patented Dec. 2. |902. R. A. FESSENDEN. SELECTIVE SIGNALING BY ELECTROMAGNETIC WAVES.

(Application led Nov. 13, 1902.)

2 Shees-Sheet 2.

(No Mmiel.)

UNITED STATES PATENT OEEICE.

REGINALD A. FESSENDEN, OF MANTEO, NORTH CAROLINA.

SELECTIV'ESIGNALING BY ELECTROMGN-ETIC WVES.

SPECIFICATION forming part of Letters Patent No.l 715,203, dated December 2, 1902; Original application led August 27, 1902, Serial No. 1 21,173. Divided and thisapplication led November 13,1902.. Serial To ali whom it may concern:

Be it known that I, REGINALD A. FEssEN-- DEN, a citizen of the United States, residing at Manteo, in the county of Dare and State of North Carolina, have invented or discovered a certain new and useful Improvement in Selective Signaling by Electromagnetic Waves, of which improvement the following is a specification.

The invention described herein relates to methods of selective multiple and multiplex signaling by electromagnetic waves in which groups of electromagnetic Waves of one kind are generated at the sending-station, the numr 5 ber of groups of electromagnetic waves per second being controlled by one or more controllers, each controller consisting of two or more mechanisms each adapted to cause groups of Waves to be emitted at a predeter- 2o mined rate per second, oneemission rate being proper to each mechanism, while at the receiving-station I employ conductors tuned to the periodicity of the electromagnetic waves generated at the sending-station and z5 one or more mechanisms in operative relation vto the conductor and arranged to produce a signal by conjoint action and each mechanism adapted to respond to one only of the emisgo sion rates of the sending end.

This application isar division of prior application, Serial No. 121,173, filed August 27, 1902.

In the accompanying drawings, forming apart of this specification, Figure 1 is a diagrammatic view illustrative of my invention. Fig. 2 is a similar view illustrating a modification of the apparatus at the nreceivi[ig-station, and Fig. 3 is adiagrammatic view illus- 4o tratin g a form of apparatus yfor multiple sending and receiving.

In the practice of lmy invention the radiat' ing-conductor l is connected to one of the sparking terminals 2, the other terminal being connected to ground. W'hile any suitable form or construction of generator-such as an induction-coil or a dynamo or dynamo and transformer, as described in my previous patents-may he employed, for convenience the 5o invention is illustrated and described `in connection with an induction-coil and batteries.l

or more receivers each consisting of two circuit.

As shown, the terminals of the secondary of the induction-coil 3 are connected, respectively, to the sparking terminals 2. The primary of the coil forms part of a circuit containing battery 4 and two or Amore make-andbreak mechanisms A and B, independently operated at predetermined but different rates of speed by any suitable means. A convenient form of make-and-break mechanism consist-s of a cup 5, containing mercury, and a pin 6, movable into and out of the mercury. A suitable means for shifting the pin consists of a small electric motor 7, having the pin so connected to its armature-shaft as to be mover.v up and down during the rotation thereof. The rotation of the motor may be 'controlled in any convenient manner, as by the tuningfork 8, which iselectrically driven and controlls by a coil on the armature-shaft of the motor the rotation of said shaft, said coil being included in the circuit with the tuningfork, this method of control being well known in the art. If the tuning-fork of the makeand-break mechanism A is adjusted to a certain number of periods-say two hundred and fifty-six (256) per secondthe motor will be so operated as to break the primary circuit of the induction-coil the same num- '4 ber of times per second. Similarly, the moadj usted to such period. It is preferable that the height of mercury in the cup should beV such (relative to the length of stroke of the pin) that the duration of contact should be several times the duration of break. A sending-key 9 or any suitable form of make-andbreak mechanism is included in the primary The sending-conductor is proportioned and arranged so as to radiate Waves of any desired single frequency-c. g., two million (2,000,000) per second.

At the receiving-station the conductor 10 has a wave-responsive device, as the loop 11, arranged in operative relation thereto, said wave-responsive device being also included' in a circuit containing two or more electromagnetic mechanisms adapted to operate in "ro which also include the coils of a telephone 14, having two or more poles. The make-aud-- break mechanisms A and B a-re preferably adjusted to operate at such rates as to produce noteswhich when combined will form r 5 a chord, and. as the tonguesof the'telephone` v12 are adjusted to respond onlyto groups of waves emitted at such rates a chord will not be produced by telephone 14 by groups of waves emitted at dilerent rates.

In lieu of the construction shown in Fig. l the receiving apparatus shown in Fig. 2 may V be used. As therein-shown, the circuits hav-` ing the mcrophonic contacts 13 also include ycontrolling devices, (such as the loops 15,) which control the currents Iin the circuits of the double movable coil-relay 16, having permanent magnets 16,. Contact-fingers 17 on the movable coils 18 of the relay are connected in the circuit, including an indicating 3o mechanism 19, said circuit being closed only when both fingers are brouglitsimultaneously against the contact-plate 20. Condensers 2l are included in each mcrophonic circuit to c'ut out steady currents; but the circuits are not electrically tuned, as such tuning is not necessary.

The method of operation is as follows: The make-and-break mechanisms A and operated at predetermined but diEerent rates, 4o the key 9 is depressed for a suflicient length of t-imeA to form a dot or a dash of the Morse code. During this period the make-andbreak mechanisms cause groups of electromagnetic waves ot' the same character and periedicity-'-i.I e., two million per second-to beemitted; but one set of groups of waves has an emission rate of two hundred and'ftysix per second and the other set of groups of waves an emission rate of, say, 'three hundred 5o and eighty-four per second. These'groups ofwaves acting on the receiving-conductor and receiving mechanism cause the tongues 13 of the electromagnetic mechanism to respond, said tongues being mechanically tuned to vibrate, respectively, at the rates corresponding to the rates of the make-and-break mechanisms A and B. These tongues actuate the mcrophonic circuits, which actuate the coils of the relay 16 toclose the indicating-circuit 6o and produce a dot or afdash. Where the loop 15 is used to operate the double relay shown in Fig; 2, the vibration of the mcrophonic contacts or tongues 13 generate a fluctuating or alternating current in the` circuit 13 15,

whichuctuating current heats up the loop 15, thereby changing the resistance in the A local circuit 18 15, and'thus changing the po- B beingA `dissolving o the insulation,

sition of the coil 18 of the double relay to complete or close the contacts at 20, vwhich contacts control the indicating-circuit. Since only one ,character of electromagnetic waves is generated and the receiving-conductor is tuned to respond only to waves of lthat character, andsince in addition the electromagnetic receiving mechanisms are mechanically tuned to respond' only to the waveemission rates at the sending end, and since also the conjoint action of the receiving mechanisms is also necessary to produce an indication, it will be seen that the system is strongly selective. y

My improvement may also be used for multiple working, as by using a plurality of tongues 13 on the electromagnetic mechanism 12, as shown in Fig. 3, and grouping them in sets-each set controlling albipolar telephone or a double movable coil-relaytwo or more messages may be received at the same time, each set of tongues being mechanically tuned to dilerent stations. It will be readily understood that each pair of makeand-break mechanisms A and B when operated by the key 9 may be used to send a message independently of'every other pair, just as if each pair were alone operating a station. Similarly, at the receiving-station the tongues 13 of one telephone 12 may be tuned to correspond to one pair of make-and-break mechanisms .A and B and receive the message sent by said pair, while a second pair of tongues may be tuned to a second pair of make-and-break-mechanisms A and B, so as to receive the message sent by such pair. Similarly, by using a plurality vof make-andbreak mechanisms at the sending-station'aud grouping them in sets, each set being capable of actuating the coil, as by operating one primary of an induction-coil having several primaries and having a secondary common to allethe primaries, several messages may be sent simultaneously, because, although both IOO pairs of make-and-break mechanisms produce an effect on a Wave-responsive device 11, the irst pair of tongues will only be affected by the rst set of make-and-break mechanisms, since the tongues are tuned to the'rst pair .only and will not respond conjointly to any other pair of make-and-break mechanisms.

respond conjointly to a second pair of makeand-break mechanisms.

' Where multiple Working is used or generally in any-case-Where heavy currents are received, it is preferred to employ two or more loops in parallel, as shown in Fig. 3, or other equivalent means-e. g., a single loop of larger cross-section, which -may be conveniently formed by ruling-aline with an insulating varnish about one one hundredth (71m) of an inch wide on a thin platinum or surface of the foil to any desired thickness, and cutting the foil into slips of the desired width.

Similarly, a second pair of tongues will only ,"ther metallic foil, plating the non-insulating".

I claim herein as my invention-.

1. In' ja system of signaling by electromagnetic waves, the combination 'at the sendingstation of means forgenerating electromagnetic Waves of the same character, means for causing the emission of such waves in two or more groups at dilerent emission rates, and at the receiving-station an indicating mechanism operative by the conjoint action of the respectively responsive devices.

2. In a system of signaling by electromagnetic waves, the combination of means at the sending-station for generatingeiectromagnetic waves oi the same character means for causing the emission of such waves in two or Amore grou ps at di ierent emission rates, means at the receiving-station responsive respectively to the groups of Waves, and an indicating mechanism operative `by the conjoint action of the respectively responsive devices.

3. In a system of signaling by electromagnetic waves, the combination of means at the sending-station for generating electromagnetic waves of the same character, means for causing the emission of such waves in two or more groupsat dilerent emission rates, meansJ at the receiving-station electrically tu'nedto respond to electromagnetic waves of the charf acter emitted, means mechanically tuned to respond respectively to the groups of waves in operative relation to thereceiving means, and an indicating mechanism operative by the conjoint action of the'mechanically-tuned respectively responsive devices.

4. In a system of signaling b y electromagnetic waves, the combination at the sendingstation of meansfor generating electromagnetic-waves of the same-character and means of causing the emission of setsv of groups of waves, each set consisting of two or more groups of diere'nt emission rates.

5. In a system of signaling by electromag` netic waves, the combination'- of a plurality of devices at the receiving-station responsive respectively to groups of waves. of different emission rates, andindicating mechanisms operative by the action of sets of the respectively responsive devices, each set consisting "my hand.

of two or more respectively responsive devices acting conjointly-.

6. In a system of signaling by electromagnetic waves, the combination oli` means at the receiving-station electrically tuned to respond to electromagnetic waves of 'a single ,periodocity, means mechanically tuned to respond respectively'to groups of dierent emission rates, in operative relation to the receiving means, and indicating mechanisms operative by the action .of sets of the mechanicallytuned respectively responsive devices, each set'consisting of two or more respectively responsive devices, acting conjointly.

7. In a system of signaling by electromagnetic waves, the combination of means at the sending-station for generating electromagnetic waves of the same character, means for causingthe emission of sets of groups of Waves, each set consisting of two or more groups of diterent emission rates, means at the receiving-station responsive respectively to the ,groups of waves, and indicating mechanisms operative bytheaction of corresponding sets of the respectively responsive devices, the components of each set acting conjointly.

S. In a system of signaling by electromag-` netic waves, the combination of means at the sending-station for generating electromagnetic waves of the same character, means for causing the emission of sets of groupsof waves,

each 'set consisting of two or more groups of different emission rates, means at the receivin'g si ation electrically tuned to respond to electromagnetic waves of the character emitted, means mechanically tu ned' to respond respectively to the groups of waves in operative relation to the receiving means, and indicating mechanisms operative by the action of corresponding sets of mechanically-tuned respectively responsive devices, the components of each set acting conjointly.

lIn testimony whereof l have hereunto set REGINALD A. FESSENDEN. Witnesses:

DARWIN' S. WoLco'r'r,

WM. H. DE LACY. 

